Fishing a volume control out of a semi-hollowbody for soldering.

Issue 94 August 20, 2009

Hey! It's crowded in here!Wiring repair:
how to work on the
electronics inside
a semi-hollowbodyErick Coleman, August 20, 2009

The bridge pickup isn’t
working on this guitar.And I think this volume control is why.The volume pot for that pickup is loose, so when you turn the knob, the control pot inside turns along with it.The guitar’s owner says it’s been this way for quite awhile. That explains the dead pickup: the back-and-forth twisting must've snapped the soldered connections on the pot or shorted the wires by touching them together.I’ll use an inspection mirror to take a look inside.

Here’s the kind of problem in there: a wire has broken off one of the contact lugs on the volume pot. That explains the dead bridge pickup. The ground wire’s broken loose from the pot case, too.

Potentiometers

So I’ve got three things to do: Resolder these connections.Tighten up the pot so the shaft won’t spin anymore.Do all of this work through the f-hole of the guitar! ($&@#%!)

I mean, take a look at the complex wiring harness that fits into a guitar like this. When you’ve got to pull all this out and put it back in, the best way is through the bridge pickup cavity  and that is really time consuming!There has to be an easier way!

Jack The GripperIt's no fun to watch the jack disappear into your guitar or amp as the nut falls off. This ingenious tool grips inside the jack to hold it steady while you adjust the nut.

Lucky for me, this volume control is close to the f-hole. There’s a good chance I can access the pot through the f-hole instead. I carefully pulled the knob off.

Knob and Bushing Puller

My secret weapon: rubber bands looped end-to-end.They go on the shaft before I drop the pot into the guitar body.

With some felt to protect the guitar, a pair of hemostats pull the pot out. (Don't let the other end of the rubber band slip into the guitar!)

Protective Felt

A piece of cardboard supports the pot over
the f-hole while I resolder the connections.

The pot goes back in through the f-hole, and the rubber bands pull it back into position (far left photo). Then the washer and nut slide down the rubber bands onto the pot shaft, and I make the nut finger-tight.

I tighten the nut once and for all with the spanner wrench. This is the time to check the other pots too and the jack, making sure they’re good and tight.